Abstract: A memory section stores values of the runout component, which are obtained in respective predetermined radial positions on the disk. A determining section selects, from the memory section, a value of the runout component corresponding to a target position. A runout detector uses, as an initial value for adaptive learning, the value of the runout component selected by the determining section, and calculates, by the adaptive learning, a value of the runout component contained in a position error between a head position and the target position. A feedforward controller calculates a feedforward value used to suppress the runout component calculated by the runout detector. A feedback controller calculates a feedback value from the position error. An adder generates, from the feedback value and the feedforward value, a control amount used to position the head in the target position.

Abstract: A method for thermally writing a magnetic servo pattern on a magnetic disc medium prior to assembling the medium in a disc drive is provided in which the medium is first magnetized in a uniform magnetization direction. A plurality of magnetic domains are then thermally written on the medium, one magnetic domain at a time, by individually heating each magnetic domain with a light beam while exposing the magnetic domain to a magnetic field. The magnetic field has an orientation that is opposite to the uniform magnetization direction. The light beam forms an illumination pattern on the medium having a shape that at least partially defines a boundary of each magnetic domain.

Abstract: Method and apparatus for detecting head landings on a data zone of a data storage disc. A disc drive includes an actuator which controllably positions a head adjacent a disc and nominally retracts the head to a parked position when the drive is deactivated. The actuator moves in response to current applied to an actuator coil immersed in a magnetic field. During disc drive initialization, the disc is accelerated to a velocity sufficient to allow the head to be aerodynamically supported over the disc, and current is passed through the actuator coil to urge the head toward the parked position. The current is monitored to detect generation of a back electromotive force (bemf) voltage induced by movement of the coil. An error condition is logged indicating that an initial position of the head was over a data zone of the disc when bemf voltage is detected.

Abstract: There is disclosed a disk drive of a perpendicular magnetic recording system including a write compensator against magnetic disturbance. The write compensator estimates strength and direction of the magnetic disturbance based on the detection result of the magnetic disturbance from a magnetic sensor during a write operation. The write compensator executes write compensation in accordance with the direction of the magnetic disturbance and the recording magnetization direction on a disk medium.

Abstract: Disclosed is a ramp used for the controlled loading of a head of a head stack assembly (HSA) onto a disk of a disk drive. The HSA includes an actuator arm, a head, and a loading surface. The ramp comprises a base structure and at least one ramp finger projecting approximately perpendicularly from the base structure. In order to load the head in a controlled manner onto the disk, the loading surface of the HSA is rotated along the ramp finger until the head is in a load position. The base structure is then actuated in a vertical direction such that the ramp finger is correspondingly actuated in the vertical direction towards the disk until the head is loaded onto the disk.

Abstract: Position error values are obtained from a transducer head while following a plurality of servo tracks with a servo loop that band-blocks a frequency range that includes F, a nominal rotation frequency. An estimated difference distribution is derived from the position error values, the difference distribution having a first frequency component at a positive frequency ?2*F. A scalar track squeeze magnitude indicator is derived from the estimated difference distribution so that the indicator to be transmitted depends on the frequency component.

Abstract: An actuator retract system and method for moving read/write heads from data regions on discs to non-data locations in a disc drive is disclosed. The non-data locations may be on or in close proximity to the discs. The non-data locations may be a landing zone or a load/unload ramp. At disc drive power-down, power generated from the rotational inertia in rotating discs is used to supply a current to a coil of a voice coil motor operably coupled to the actuator. During such power-down operation, a desired velocity is maintained using acceleration or deceleration, when necessary. The current generates an electric field around the coil that interacts with a magnetic field in the voice coil motor to move the actuator such that the read/write heads are retracted to the non-data location.

Abstract: For runout compensation in a data handling system, a servo feedback loop is configured to control a head position relative to a corresponding disc surface. Operation of the feedback loop is complicated by a repeatable error in the head position having energy at harmonics of the spindle rotation frequency. Also, the feedback loop has a gain with a frequency sensitivity in a target frequency range. A feedforward controller generates an output injected into the feedback loop based on an error-indicative input. This defines a feedforward closed-loop transfer function, between the loop output and the feedforward controller input. The feedforward controller prevents the frequency sensitivity from substantially varying the feedforward closed-loop transfer function gain and phase within the target frequency range, thus reducing computational burden.

Abstract: A device for generating synchronous numeric signals, including a first signal generator which supplies a numeric reference signal having a first frequency and a first period; and a second signal generator which generates an internal numeric signal having a second frequency and a second period, and a synchronized numeric signal. In addition, the second signal generator includes a predictor which generates, with a third period and a third frequency higher than the first frequency and the second frequency, estimated samples correlated to a current sample and to a predetermined number of former samples of the internal numeric signal. The predictor, in turn, includes a selection circuit controlled by the first signal generator for selecting one among the estimated samples in each reference period, the synchronized numeric signal being formed by the selected estimated samples.

Abstract: An apparatus and associated method are disclosed for compensating for repeated servo runout error in a disc drive. The disc drive includes a disc on which servo information is arranged as a plurality of servo fields which define tracks on the disc. An actuator assembly is provided adjacent the disc and includes a head which accesses the servo fields and an actuator motor which moves the head relative to the disc. A servo circuit controls radial location of the head by applying current to the actuator motor in response to the servo information. The repeated servo runout error, caused by errors in the radial location of the servo fields on the disc, is compensated by the servo circuit through the use of compensation values which are stored in compensation fields of the servo fields.

Abstract: An automated data storage library includes a plurality of storage slots, a drive having a stacked connector system, and a library control manager configured to monitor usage data for the stacked connector system representative of the number of times the stacked connector system is mounted by a media connector from any of a plurality of media elements, and wherein the library manager is further configured to coordinate refreshment of the stacked connector system when the usage data reaches a predetermined usage level threshold. The stacked connector system may be refreshed by replacement or addition of a separate connector. Various methods of improving the long term performance of a drive in a media library by replacing or adding a connector to a stacked connector system of a drive are also provided.

Abstract: A data storage magnetic tape uses a volume control region (VCR) that contains all of the control information for the tape. There is a large span of blank tape after the VCR region before the actual data storage region of the tape. When a tape drive spools the tape between the VCR and data storage region, the tape motion is continued past the VCR region, after the VCR region is updated, into the region of tape where there is no data of any kind. Just before reaching the data storage region, the motion of the tape is reversed and the tape is rewound into the cartridge. The portion of the tape that experiences the motion reversal is prone to be thrown such that it protrudes from the other layers of uniformly layered tape. Even if these thrown wraps are damaged, this portion of the tape has no stored data, which increases the overall reliability of the information stored on the tape.

Abstract: Vibration detector receives as an input a relative displacement signal corresponding to a displacement distance of fine actuator, and extracts only a high frequency component. Fine actuator is driven according to a composite signal generated in fine motion corrector by combining the high frequency component with fine motion control signal produced on the basis of position error signal. In addition, coarse actuator is driven according to a composite signal generated in coarse motion corrector by combining the high frequency component with coarse motion control signal produced on the basis of the relative displacement signal. According to the above configuration, a head positioning device employing a two-stage actuator is able to perform positioning control with stable operation even when it receives external disturbances such as vibrations and impacts.

Abstract: A read/write head microactuator includes first and second insulating deposits that are flat, spaced apart by an air gap, and laterally movable responsive to a microactuator electrical drive current. First and second flat, interdigitated drive electrode deposits are deposited on the first insulating deposit. A flat, digitated sense electrode deposit is deposited on the second insulating deposit. The sense electrode deposit provides a relative position output. The sense electrode deposit faces both the drive electrode deposits across the air gap.

Abstract: A method is disclosed for defining tracks on a rotating magnetic disk medium of a disk drive. Reference tracks are followed using a servo control loop while writing servo burst patterns defining a first target servo track. The servo control loop includes a two-dimensional digital state compensator having a first input that receives position error signals, a first output that generates control signals for positioning a transducer head, a second output that generates track-following state variables, and a second input that receives stored track-following state variables. The first target track is followed using the servo control loop while servo burst patterns are written, and while the stored track-following state variables corresponding to the servo burst patterns defining the first target track are applied to the second input.

Abstract: An apparatus and method of correcting for written-in repeatable run-out in a disc drive having a servo loop for positioning a head over a rotating disc is provided. The rotating disc has at least one data track and servo information recorded in a plurality of servo fields along the data track. An initial written-in repeatable run-out compensation value for each servo field is computed as a function of a position error signal generated for each servo field during a first revolution of the disc. The initial written-in repeatable run-out compensation value for each servo field is then injected into the servo loop during another revolution of the disc. A compensated position error signal for each servo field is computed as a function of the initial written-in repeatable run-out compensation value for each servo field. A refined written-in repeatable run-out compensation value for each servo field is then computed as a function of the compensated position error signal for each servo field.

Abstract: First and second integrating circuits are connected to both terminals of an impact sensor, and a difference between integration outputs of the integrating circuits is obtained by a differential amplifier. Voltage waveforms result from an input offset voltage in output terminals of the first and second integrating circuits and thereby cancel each other out. In essential impact detection, a comparator compares a differential output of the differential amplifier with a threshold level, whereby impact detection is performed.

Abstract: A disk drive is disclosed comprising a disk, a spindle motor for rotating the disk, an actuator arm, and a head coupled to the actuator arm. While powered down the head is latched in a parked position. During a start-up process, the spindle motor is controlled to rotate the disk toward an operating speed and the head is unlatched prior to the disk reaching the operating speed. If the disk drive is in a first spin-up mode (e.g., a normal spin-up mode) the head is unlatched relative to a first target speed, and if the disk drive is in a second spin-up mode (e.g., a re-sync spin-up mode) the head is unlatched relative to a second target speed greater than the first target speed.

Abstract: Non-linearity in a position error signal (PES) for a data storage device is precisely characterized during a calibration phase in the manufacturing process. From this characterization of the PES non-linearity, the data storage device can be programmed with the necessary data to perform accurate, real-time linearization calculations of the PES in order to compensate for non-linearity in the PES during operation. The sequence of calibration steps includes a PES gain calibration, a first servo loop gain calibration, a PES linearization calibration, and an optional second servo loop gain calibration.

Abstract: A disk-shaped magnetic recording medium having a reference track and a plurality of data tracks is rotated by a motor which generates an index signal at a predetermined position. A magnetic head is slightly moved in the radial direction of the medium for each predetermined unit distance smaller than the data track width, and a reproduction output amplitude measuring circuit measures the reproduction output amplitude of a signal read from the data track for each index signal. A CPU obtains a position where the amplitude has the maximum value based on the number of head movements and the amplitude at that time so as to control data track positioning. Further, the CPU calculates a relative position between the data track position and the reference track position to perform reference track positioning. The data or reference track positioning of the magnetic head can be performed accurately in a short time.